Compressing Request Body - mathieuboniface/gatling GitHub Wiki

Compressing Request Body is something that should be supported out of the box by async-http-client, but it's sadly currently broken.

Have faith, Gatling user, there's a work around! Let's compress the body manually and pass it to byteArrayBody.

The exemple below use JZlib in order to compress the outcome of a Scalate ssp template. The lib has to be provided in the classpath (add to the lib directory if running from CLI). Of course, one can use the regular yet less efficient java.util.zip.GZIPOutputStream.

// note: pass parameters as Strings so we can transparently set up extra bindings
// otherwise, explicitly define all the bindings in the ssp file
def generateGzippedBytesFromSsp(templateName: String, attributes: Map[String, String]) = {

  import java.io.{ ByteArrayOutputStream, PrintWriter }
  import org.fusesource.scalate.{ Binding, DefaultRenderContext }
  import com.excilys.ebi.gatling.http.request.builder.AbstractHttpRequestWithBodyBuilder
  import com.excilys.ebi.gatling.core.util.IOHelper
  import com.jcraft.jzlib.GZIPOutputStream

  val out = new ByteArrayOutputStream

  IOHelper.use(new PrintWriter(new GZIPOutputStream(out))) { pw => // just a borrow pattern
    val extraBindings = attributes.keySet.map(Binding(_, "String"))
    val renderContext = new DefaultRenderContext("templateName", AbstractHttpRequestWithBodyBuilder.TEMPLATE_ENGINE, pw)
    for ((key, value) <- attributes) { renderContext.attributes(key) = value }

    AbstractHttpRequestWithBodyBuilder.TEMPLATE_ENGINE.layout(templateName, renderContext, extraBindings)
  }
  
  out.toByteArray
}

val users = scenario("RequestCompression")
  .exec(
    http("Gzip")
      .post("postUrl")
      // important: properly set header so the server understand the request is compressed
      .header("Content-Encoding", "gzip")
      .byteArrayBody { session =>
        // assumes there's a "foo" attribute in Session
        val sspParams = Map("foo" -> session.getAttribute("foo").toString)
        generateGzippedBytesFromSsp("template.ssp", sspParams)
      })